ErrorCodeDoctor
Daikin · Air Conditioner

Daikin Air Conditioner A4 error code

Difficulty: Hard · Cost: $80–$250 · Duration: Requires professional service

The A4 error means your Daikin air conditioner's freezing protection activated. This applies to water-cooled or hydronic indoor units and indicates a shortage of water volume, a low water temperature setting, or a defective water temperature thermistor. Contact a qualified technician to inspect the water circuit and thermistor.

Common causes

  • Shortage of water volume in the water circuit
  • Water temperature setting is too low
  • Defective water temperature thermistor

How to fix it

  1. 1

    Contact a qualified technician to inspect the water volume, temperature settings, and thermistor

Related Daikin Air Conditioner error codes

1

A0

An external protection device connected to the indoor unit has been activated

hard
2

A1

A fault was detected in the indoor unit PCB (control board)

hard
3

A3

The drain level control system has detected an abnormality — drain may be clogged

medium
4

A5

Freeze-up protection (cooling) or high pressure control (heating) has activated — check the air filter

easy